Alexander Blackman admitted today he would understand if his wife Claire had left him as he languished in jail for shooting dead a Taliban fighter.

Marine A spent more than three years in prison after being jailed for life at Bulford Court Martial in 2013 over the fatal shooting of an injured Afghan insurgent in 2011.

He was released last month after a campaign led by Mrs Blackman and backed financially by Mail readers helped quash his murder conviction.

He said: 'If Claire did not want to stick around or if she wanted to part company, it would be something I’d understand'.

In their first TV interview together today Mrs Blackman, who he describes as his 'wife in a million', then interjected with a strong 'no', adding: 'My marriage vows are my marriage vows'.

Honest: Alex Blackman, with his wife Claire, says he spent long periods during his time in jail considering why he killed the insurgent in 2011 and would understand if Mrs Blackman had left him

Sgt Blackman, left and right, was finally released from HMP Erlestoke in Wiltshire following an Appeal Court decision in March to quash his conviction of murder for shooting a mortally wounded Taliban fanatic in Afghanistan in September 2011

On December 6, 2013, Al was sentenced to life in prison with a minimum term of ten years - he is now a free man after his sentence was cut and is back with his beloved wife

Sergeant Blackman – known as Marine A at his military trial – was saved by a campaign for justice spearheaded by his loyal wife.

Speaking to the Mail in a world exclusive over the weekend he said: 'I will be eternally grateful to Claire and I cannot put into words how wonderful she is.

‘She is a wife in a million. Other inmates often said how lucky I was to have her fighting so hard for me. I don’t think there is anybody who has witnessed the effort she has gone to who will doubt how she feels about me, and that’s beyond words really. You just can’t imagine anyone cares for you that much'.

In another interview today Mr Blackman said he cannot explain why he shot dead a Taliban fighter - and is unsure if he would do it again.

The Royal Marine said he spent long periods during his time in jail considering why he killed the insurgent in 2011.

In March his murder conviction was finally overturned after prosecutors accepted Sgt Blackman was ‘unequivocally’ suffering from mental disorder at the time.

Asked why he did it he said: 'I really couldn't tell you. Like I say I have spent a lot of time thinking about it and I haven't got a definitive answer.'

He referred to a previous description of the killing as 'a moment of madness'.

Sgt Blackman was convicted after video footage secretly filmed on a head camera worn by a fellow marine captured him shooting an insurgent - but his murder conviction was overturned after a campaign led by his wife and backed by Mail readerfs

The murder verdict was quashed by the Court Martial Appeal Court and replaced with diminished responsibility manslaughter in March.

Five judges ruled Blackman was suffering from an 'abnormality of mental functioning' at the time of the incident, when he was serving with Plymouth-based 42 Commando.

His sentence was reduced to seven years, meaning he was eligible for release on licence after serving half the term.

Mrs Blackman told the BBC: 'I feel personally fairly certain that if he had a time machine and could go back and do things differently he absolutely would.'

The pair said they were delighted to be reunited after he was released from HMP Erlestoke in Wiltshire at the end of April.

Previously Blackman's lawyer Jonathan Goldberg QC said the story has attracted attention in Hollywood, naming Tom Hardy and Kate Winslet as potentials to play the couple on the big screen.